The present invention relates to a method and apparatus for making wire binders for steno pads, calendars, brochures and like commodities wherein a stack of sheets is held together along one edge so that the sheets can be flipped about an axis which is defined by the properly inserted binder. More particularly, the invention relates to improvements in a method and apparatus for converting a length of wire into an undulate web and for thereupon converting the undulate web into a substantially C-shaped body which is ready to be subdivided into discrete binders.
It is already known to convert a straight metallic or plastic wire, which is withdrawn from a barrel, reel or another suitable source of supply, into a meandering or undulate web whose loops are located in or can be moved into a common plane. Such web is thereupon bent along an axis which extends lengthwise of the web to achieve the conversion into a C-shaped or trough-shaped structure having prongs along one or both marginal portions so that it can be introduced into the registering perforations of stacked sheets preparatory to conversion of individual C-shaped constituents into rings. The conversion of straight wire into an undulate or meandering web can be carried out in a machine of the type disclosed in the commonly owned U.S. Pat. No. 4,165,767 granted Aug. 28, 1979 to Seaborn and Lemburg. The web is converted into a C-shaped structure by resorting to several deforming tools, e.g., two pressing tools, and to a conveyor system which advances the undulate web through the deforming station in stepwise fashion. During each interval between successive stepwise advances of the undulate web, the marginal portions of such web are treated by one of the deforming tools and the median portion or the regions bounding the median portion of the web are thereupon treated by another deforming tool. Reference may be had to U.S. Pat. No. 4,047,544 granted Sept. 13, 1977 to Paul Seaborn et al. A drawback of such intermittently operated apparatus is that their output is relatively low. Therefore, apparatus of the type disclosed in U.S. Pat. No. 4,047,544 are not directly coupled to machines which can turn out undulate web of metallic or plastic wire at a relatively high rate of speed. In other words, the patented apparatus cannot be used as a constituent of a complete production line which converts wire into binders, which assembles or otherwise treats stacks of sheets, and which inserts binders into discrete stacks. Certain stacks can be held together by a single binder, and certain other stacks are held together by two or more converted C-shaped or trough-shaped binders.